Method of and apparatus for cleaning coal



Nov. 26, 1935. J. H. DICKERSON METHOD OF AND APPARATUS FOR CLEANING GOALFiled Sept. 1, 1955 2 Sheets-Sheet l elzqrzes fjiflz'ckersan 26, 1935.J. H. DICKERSON METHOD OF AND APPARATUS FOR CLEANING GOAL 2 SheetsShee 2Filed Sept. 1, 1933 v I awe/who e, Jamasflflicierson Patented Nov. 26,1935 UNITED STATES PATENT OFFICE LIETHOD OF AND APPARATUS FOR CLEANINGCOAL 4 Claims.

Method of and apparatus for cleaning coal This invention relates toimprovements in pneumatic separators, used to remove refuse from coal orother material. It refers to a type of cleaner having a pervious riilleddeck with a rocking reciprocating motion, together with a current of airpassing through it upwards, causing the coal to spread out and pass tothe lower side of the table, while heavier gravity material is trappedand propelled forward along the riilles to a. stream of refusedischarging ahead.

One object of this invention is an improved feed arrangement in which acurrent of air is passed thru a thin stream of raw coal below thefeeder, and some of the heavier gravity material is separated from thecoal before it touches the deck.

A further object is to provide a free passageway for refuse along thedeck below the feeder, and avoid all interference from the raw coal.

Another object of the current of air is to give the coal betterpreparation for cleaning by loosem'ng up the coal, separating piecesheld together by clay or moisture, and raising most of the dust at onepoint to facilitate dust collection.

The invention in one of its forms relates to a pneumatic separatorhaving a pervious diagonally riflied forwardly moving reciprocatingdeck, means to feed a thin longitudinal stream of raw materialdownwardly to the upper side of said deck, means to provide a current ofair upwardly through the perforated deck, means to provide a stream ofair to intercept said stream of raw material from behind before ittouches the deck, and a passageway below the feed means and behind thestream of raw material for the free forward movement of the heavygravity material as it passes across the feed stream directed by thediagonal rifiles and movement of the deck, while the lighter materialpasses over the riflles to the lower side of the deck causing aseparation. In a more specific aspect of the invention, control gatesare provided extending longitudinally of the deck, said gates beingseparated from the deck and a feed plate is positioned adjacent to thegates, these elements cooperating to deliver the feeding materials in athin longitudinal stream substantially parallel to the forward movementof the deck, while preventing any substantial grinding of the coalbetween the deck and the feeding elements.

The invention is also directed to a method of separating raw materialsof different specific gravities, such as coal and refuse, although it isobvious that the method may be applied to other materials, a mixture ofcoal .and refuse merely serving to illustrate a preferred material towhich the process may be applied. The material is fed in a thinfreely-flowing stream upon a reciprocat- 5 ing support and a partialseparation in the stream is effected by directing a current of air tothe stream to cause the coal to be directed out of the feed stream andupon the support while some of the heavier impurities fall on the 7support behind the stream. Thereafter, the partially purified coal isStratified upon the support or deck by the combined action of thereciprocating motion or its equivalent and upwardly directed aircurrents or its equivalent. Of course, the stratification is facilitatedby combining with the above elements a rocking motion. Impuritiessettling on a portion of the support cross under the feed stream to jointhe impurities previously separated from the feed stream and then aredirected forwardly without further interference with the feed streamforming a refuse stream receiving impurities directed to it from otherparts of the support.

Other objects improving the emciency of the cleaner will be apparentfrom the following description.

The above objects are attained by mechanism illustrated in theaccompanying drawings, in which- Figure 1 is a cross section showing oneform of the improved feed parts.

Figure 2 shows these parts as installed on a type cleaner now used.

Figure 3 shows a side elevation, and Figure 4 a plan of improved feederparts as installed on an existing separator.

Figure 5 is a comprehensive plan of a type deck to which the improvedfeed arrangement may be added.

Figure 6 shows a cross section of a deck sloping to one side with acurrent of air intercepting the flow of coal from an improved feed chuteand rotary feeder.

Similar numerals refer to similar parts throughout the several views.

Longitudinal feed control gates I nearly touch the deck 4 before theyare shortened for the improved feed device, and before the oldperforated feed plate 2 is removed. Surge bin 3 usually has a capacityof five tons or more. Feed plate 5 is solid and. may be made with aridge top as shown or have it rounded. A current of air 6 flows thru theopening below the feed plate to intercept the thin stream of raw coalpassing to the deck. A'55.

' way slate and other refuse is removed along the lane or passageway 1below the feed plate 5 and current of air 6 permits the free passage ofrefuse forward to the slate channel I I. Refuse 8 is indicated by thecoarser and clean coal 9 by the finer material, but this is forillustration and does not show relative size, as coal may be as large asthe slate. Rifiles ID are partitions which retard the movement ofmaterial by gravity and trap the slate. The refuse banks against thebanking bar I2. The product hoppers I3, 14, and i5 are for clean coal,middlings and refuse respectively. Eccentrics l6, motor H, andconnecting rods I8 are parts for one form of drive. A wide chute l9 androtary feeder 2B show a type of feed independent of the deck motion.Plate 2| may be bent to direct or regulate theflow of air current 6. Aperforated plate or screen 22 is placed in bottom of chute IQ for a flowof air from pipe 23. Depth of coal in chute I9 is controlled by the gate24 and the feeder 20, but any form of feeder and gate may be used; i

' As shown in Fig. 5, the deck is provided with a perforated feed plate2. The present invention is directed to improvements on such prior artfeed plates. Instead of using the feed plate such as shown in Fig. 5, inthe present invention, there is provided a feed plate 5 which cooperateswith the gates l to deliver a thin stream of material downwardly to thedeck.

Method of operation, and further explanation of functions With the typefeeder having wide gates coming close to the deck to regulate the flowof coal between their lower edges and the deck, and aperforated feedplate on the deck between the gates, the weight of coal above the feedercauses such pressure on the bottom of the deck and. against the gatesthat very little air can work up into the coal. Refuse collected alongthe riffles and guided into the coal coming out from beneath the gatesunder pressure is thrown back into the coal and can not get into theslate channel until it has passed the forward part of the feeder gates.If

plate attached rigidly above the deck, and the gates shortened tosubstantiallythe same level as the lower part of the feed plate, the rawcoal is still fed to the deck by its own action and the I capacity isregulated by the adjustment of gates inwardly or outwardly as shown inFig. 2. There is very little degradation as the coal is not groundbetween the deck and the gates. The coal leaves the feed plate in a thinstream and a current of air passes thru it floating the lighter materiala little forwardly, and some of the refuse is dropped before it reachesthe deck. This refuse is carried along the slate lanes 1 until the endof the feed surge bin 3 is passed. Then the slate streams unite in themain slate channel I I. The riffles I trap the slate and material tooheavy to be lifted over them by the deck'action and the air current,guiding it forward into the refuse lanes 1. In this side of the feeder,5, without being thrown back 'into' the coal, congestion ahead of thegates is stopped, and the efficiency of the whole deck is increased.

For a deck discharging on one side only the same arrangement may be usedwith feed plate sloping in one direction. An alternate plan is to shownin Figure 1 so the latter will become a distributor. Another arrangementis ,to provide a wide chute l9 with a rotary feeder 26, a gate 2-1 abovethe feeder to control the depth of coal, and 15 a short chute below thefeeder as shown in Fig. 6.

Where the separator has one or more cleaning areas it may be fed by arotary feeder with an aerating chute as just described. The deck willhave a reciprocating or vibrating motion which 20 will'propel refuseforward along the riffies to the slate lanes and channels, hence to thepoint of refuse discharge. The diagonal type of riiiles is used tospread the coalout over a longer deck. The motion of the deck and theair bring the 25 lighter material or coal to the top and over theriffles, while the slate sinks to the bottom where it is trapped by therifiles and guided by them at an angle to the flow of the coal. For asingle deck sloping to one side the lighter material or coal 0' havingpassed over the rifiles to the edge of the deck drops into producthoppers.

Certain subject matter originally present in the case, as filed, is nowclaimed in copending' applications, Serial No. 18,029, filed April 24,1935, 5

tending longitudinally of the deck and separated 45.

from the deck, a feed plate positioned adjacent to saidgates, said gatesand feed plate delivering feeding material in a thin longitudinal streamsubstantially parallel to the forward movement of the deck whilepreventing any grinding of the 50 coal between the deck and feedingelements, means for feeding air in a direction substantially transverseto said feed stream to intercept said feedstream before the feedmaterial touches the deck of the separator, whereby the coal is moved 55forward and some of the heavier gravity material is forced downwardlybehind the forwardly moving stream, and a passageway below and behindsaid longitudinal stream of material adapted to receive the heaviergravity compo- 60- nents which are directed thereto, and reciprocatingmeans for moving the heavier gravity material along the table andthe-coal transverse thereto.

2. In a pneumatic separator for separating ma-' 6 terial comprising alight gravity component and a heavier gravity component, the combinationof a pervious diagonally rifiled reciprocating .deck having cleaningsections sloping respectively from the center of the table, a feederseparated from 70 the table deck and discharging centrally andlongitudinally of the deck to each side of the deck thin streams of rawmaterial, means for applying a current of air to eachlongitudinallyfthin stream to intercept the material fed, to the deck 75before the material touches the deck whereby the lighter material ispositioned to be moved transverse of the latter under the influence ofthe reciprocating table and the air issuing through the pervious deck,and some of the heavier gravity component dropped down behind theforwardly moving stream, and a passageway below and behind each of saidlongitudinal streams of material, said passageway being adapted toreceive the heavier gravity components which are directed thereto.

3. In a pneumatic separator, the combination of a pervious diagonallyriflled forwardly moving reciprocating deck, means to feed a thinlongitudinal stream of raw material downwardly to the upper side of saiddeck, means to provide a current of air upwardly through said perforateddeck, means to provide a stream of air to intercept said stream of rawmaterial from behind before it touches the deck, a passageway below saidfeed means and behind said stream of raw material for the free forwardmovement of the heavier gravity material after it passes under the feedstream directed by the diagonal riflles and movement of the deck, whilethe lighter material passes over the riflles to the lower side of saiddeck causing a separation.

4. The method of separating raw materials 5 of different specificgravities such as raw coal comprising feeding the material in a thinfreely flowing stream upon a reciprocating support, effecting a partialseparation in the stream by directing a current of air to the stream tocause 1 the coal to be directed out of the feed stream and upon thesupport while some of the heavier impurities fall on the support behindthe stream, stratifying the partially purified coal upon the support byreciprocating motion and upwardly 15 directed air currents, anddirecting the impurities settling on a part of the support to crossunder said feed stream to join the impurities previously separated fromthe feed stream and then forward without further interference with thefeed stream 20 forming a refuse stream receiving impurities directed toit from other parts of the support.

JANIES H. DICKERSON.

